Study On The Mechanism Of Sliding And Cracking Failure Of The Rock Slope In The Smooth Layer

The rock slope in the smooth layer is widely distributed in China,which is the most common rock mass engineering in the construction of highway,railway,Water conservancy and other infrastructure.Sliding-cracking failure,as a failure mode of the Laminar rock slope,is high and harmful in the failure of the slope of the smooth layer.In this paper,theoretical derivation and numerical simulation method are used to study the failure mechanism of sliding-cracking smooth rock slope under the action of Seismic force,the main research results are as follows:(1)On the basis of the engineering geological classification of the slope,several common instability failure modes of the bedding slope are summarized from two aspects of geometrical morphology and failure mechanics mechanism.In particular,the geological and mechanical characteristics of sliding-fracturing smooth rock slope are discussed,its deformation evolution process and the main factors affecting its stability are expounded,and its failure mechanism is preliminarily evaluated.(2)The failure forms of the rock slope of the smooth layer are divided into three categories,which are the collapse and damage when the inclination of the rock layer and the excavation angle of the slope are large respectively,and the sliding and cracking failure of the excavation slope angle is larger than the inclination of the rock layer and the slip-bending crack failure of the excavation slope is less than or equal Aiming at the situation that the slope angle of excavation is larger than the inclination of rock layer,the mechanical model is established by using limit equilibrium method,the calculation formula of transverse instability length of interlayer rock layer is deduced,and the parameter sensitivity analysis of each influencing factor of the formula is carried out.Then the feasibility of this formula calculation is verified by an example of the excavation point of a mileage section in Qianjiang Expressway.(3)Aiming at the situation where the slope angle of excavation is less than or equal to the inclination of rock layer,the mechanical model is established by using the elastoplastic plate theory,the calculation formula of bending section length when the rock layer of the laminar rock slope is slid and bent,and the influence of rock thickness,seismic force coefficient and plastic parameters on the length of bending section is analyzed.The formula is applied to the rock slope of a certain layer,and the results show that it is good.(4)Using MIDAS GTS NX software to carry out two-dimensional numerical simulation analysis of the failure of the Laminar rock slope,and establishing the failure mechanism analysis of the numerical model of 11 groups of two-dimensional smooth rock slope on the thickness of rock layer,the inclination of rock layer,the combination of soft and hard interlayer,the adhesion force and the internal friction angle 5 factors,Results The instability of the laminar rock slope was characterized by significant rock thickness,rock inclination,soft and hard interlayer,adhesion force and internal friction angle effect.(5)In this paper,the transverse instability length of a excavation section of the new Qianjiang Expressway is calculated,and the stability of the slope is evaluated qualitatively and quantitatively by combining the geological data of the slope engineering.Then a three-dimensional numerical analysis model of the slope is established to analyze the deformation and failure process of the slope.Through comparison,it is found that the numerical simulation results are consistent with the actual field survey data when the slope is excavated and destroyed in 2007.